12ft or 15ft telescoping ladder?

[CJ M.]

I don't do much maintenance on my properties, but just realized I don't own a ladder!

I really like the Xtend telescoping ladders from Sherman Williams since (I don't own a truck). They have both 12 and 15 ft versions. What would be the better "all purpose" size for someone like me who will occasionally use it? Will a 12 footer get me on the roof of a single story house? Should I go with the longer 15 footer "just in case?"

Thank you